MRI is an imaging method which magnetically excites nuclear spin of an object (a patient) placed in a static magnetic field with an RF pulse having the Larmor frequency and reconstructs an image based on MR signals generated due to the excitation. The above-described MRI means magnetic resonance imaging, the RF pulse means a radio frequency pulse, and the MR signal means a nuclear magnetic resonance signal.
Here, an RF (Radio Frequency) coil device is a device which transmits an RF pulse to nuclear spin inside an object by, for example, supplying a coil with an RF pulse electric current and receives generated MR signals.
Some of RF coil devices are built-in type included in an MRI apparatus and other RF coil devices are recognized by a control unit of the MRI apparatus by being connected to a connection port of the MRI apparatus such as local RF coil devices, for example.
Various types of the local RF coil devices are used in accordance with an imaging part. For example, in the case of imaging of a shoulder joint, a dedicated RF coil device for a shoulder joint is set on the shoulder of an object.
As a method of transmitting MR signals received by an RF coil device to a control side of an MRI apparatus, a wired transmission method and a radio transmission method in which MR signals are converted into digital signals and then wirelessly transmitted are known.
It is preferable that noise mixed with MR signals is as small as possible in terms of improving imaging quality regardless of methods of transmitting MR signals received by an RF coil device to a control side of an MRI apparatus.
Therefore, a new technology to suppress mixing of noise into MR signals by simple device configuration has been desired in MRI.